Self-filtering seal for bearing

Abstract

A self-filtering sealing element for a bearing comprises a sealing lip and a framework arranged in the sealing lip, the sealing lip comprises an upper sealing lip and a lower sealing lip, the framework comprises an upper framework and a lower framework which are located in the upper sealing lip and the lower sealing lip respectively, and a self-filtering assembly is arranged between the upper framework and the lower framework. And the self-filtering assembly is used for communicating the bearing rolling channel with the outside and filtering impurities in external oil. The self-filtering sealing piece has the beneficial effects that the self-filtering assembly is integrated between the upper framework and the lower framework, and the dual functions of communication and isolation of the inner space and the outer space of a bearing are achieved structurally.

Description

Technical Field

[0001] This invention relates to a seal, and more particularly to a self-filtering seal for bearings. Background Technology

[0002] In the design and application of gearbox bearings, there is a close correlation and inherent conflict between bearing cleanliness and its own lubrication requirements. On the one hand, high cleanliness is the foundation for ensuring long-term reliable bearing operation. Impurities can cause raceway crushing and accelerated wear, thereby shortening bearing life and causing NVH problems. On the other hand, bearings must be continuously lubricated to reduce friction and heat accumulation. Traditional sealed bearings achieve initial lubrication by injecting grease, but the grease is gradually consumed after prolonged use, and lubrication is then replenished by the oil in the gearbox. This dependence creates a linkage: the cleanliness of the gearbox oil directly affects the bearing's lubrication effect and operating environment. However, the conflict is thus highlighted: the lubrication process itself may introduce or carry impurities, which can easily penetrate into the bearing under high-speed operation, destroying its cleanliness. On the other hand, excessive pursuit of cleanliness may limit the choice of lubricant or increase system costs, making it difficult to balance both aspects in the design.

[0003] Existing technologies have significant shortcomings in balancing bearing cleanliness and lubrication requirements. While traditional sealed bearings can isolate contaminants in the short term, once the internal grease is depleted, lubrication must rely on gearbox oil, the cleanliness of which is difficult to guarantee absolutely. Impurities such as metal particles or dust entering the bearing create raceway pits under high-speed rolling, leading to a sharp decline in bearing life and causing NVH problems such as abnormal noise. Recent road tests and bench tests have frequently reported that even with sealed bearings, impurities can still penetrate under high-speed conditions, causing pitting and performance degradation. This highlights that existing sealing and lubrication solutions cannot effectively resolve the conflict between cleanliness and lubrication, thus limiting the reliability and durability of gearbox bearings. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a self-filtering seal for bearings that effectively filters impurities while using gearbox lubricating oil to lubricate the bearing, thereby improving bearing reliability.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows: A self-filtering seal for bearings includes a sealing lip and a skeleton disposed in the sealing lip. The sealing lip includes an upper sealing lip and a lower sealing lip. The skeleton includes an upper skeleton and a lower skeleton respectively located in the upper sealing lip and the lower sealing lip. A self-filtering component is disposed between the upper skeleton and the lower skeleton. The self-filtering component is used to allow the bearing rolling track to communicate with the outside world and filter impurities in external oil.

[0006] The beneficial effects of this invention are as follows: This self-filtering seal integrates a self-filtering component between the upper and lower skeletons, structurally achieving a dual function of connecting and isolating the internal and external spaces of the bearing. On the one hand, it allows the lubricating oil from the gearbox system to enter the bearing for lubrication, thereby replacing the traditional pre-lubricating grease method, fundamentally avoiding the compatibility risks that may exist between grease and gearbox lubricating oil, and simplifying the initial lubrication process of the bearing. On the other hand, the self-filtering component, as an active barrier, can intercept impurities in the lubricating oil before it enters the bearing raceway, effectively preventing contaminants such as metal particles and dust from intruding into the critical friction areas inside the bearing. This avoids high-speed crushing of impurities between the rolling elements and the raceway, reducing the possibility of pitting damage to the raceway, significantly improving the durability and operational stability of the bearing under long-term high-speed operating conditions, and helping to reduce NVH problems such as abnormal noise caused by bearing damage. As a preferred approach, the self-filtering assembly can be designed as an annular filter unit composed of a support frame and multiple layers of filter media. The outer edge of the unit is fixedly connected to the upper and lower skeletons through vulcanization or adhesive bonding processes to form a stable rigid support. After the lubricating oil permeates from the outside through the multi-level pores of the filter unit, the clean oil can reach the inner bearing rolling track area, thus achieving continuous and active filtration and lubrication.

[0007] Furthermore, the self-filtering assembly includes an outer filter layer disposed on the side closer to the outside and an inner filter layer disposed on the side closer to the rolling track, wherein the pore size of the outer filter layer is larger than that of the inner filter layer.

[0008] This solution employs a dual-layer gradient filtration structure, from the outside in. The outer filter layer, acting as the first line of defense, intercepts larger particulate impurities in the lubricating oil, performing preliminary "coarse filtration" to effectively prevent large particles from clogging the subsequent fine filtration structure, ensuring long-term unobstructed flow of the lubricating oil. The inner filter layer, as the second line of defense, is responsible for fine filtration of the pre-filtered oil, capturing even smaller harmful particles, ultimately providing high-cleanliness lubricating oil for the bearing's rolling raceway. This staged filtration mechanism not only enhances the overall filtration capability for impurities of different particle sizes but also reduces the workload and clogging rate of the inner filter layer by pre-intercepting large particles through the outer filter layer. This extends the maintenance cycle and service life of the entire self-filtering assembly, ensuring that the bearing receives stable and clean lubrication over the long term. As a preferred approach, the outer and inner filter layers can be made of metal wire mesh or non-metal fiber felt with different weaving densities or sintered pore sizes. Both are fixed together on a ring-shaped rigid support frame by covering or embedding. This support frame is then connected to the upper and lower frames to ensure that the filter layer is structurally stable and does not deform or shift under working pressure.

[0009] Furthermore, the pore size of the outer filter layer is ≤10μm, and the pore size of the inner filter layer is ≤5μm.

[0010] By specifically defining the upper limits of the pore sizes of the outer and inner filter layers, a clear technical boundary is provided for filtration performance. Controlling the pore size of the outer filter layer to 10 micrometers or less effectively intercepts most of the larger metal shavings generated by wear and larger dust particles from external sources in the lubricating oil. These particles are the main threat causing early indentation damage in the raceway. Further strictly controlling the pore size of the inner filter layer to 5 micrometers or less captures even finer wear particles that might penetrate the first line of defense. While these tiny particles are individually less harmful, their accumulation in large quantities can accelerate wear and affect oil film quality. This pore size configuration ensures a sufficiently high cleanliness standard while also considering the permeability of the lubricating oil, avoiding the problem of excessive flow resistance due to excessive filtration precision, which could affect the timely and sufficient supply of lubricating oil. It achieves a good balance between filtration efficiency and flow efficiency.

[0011] Furthermore, the self-filtering assembly also includes a metal clamping plate disposed between the outer filter layer and the inner filter layer. The metal clamping plate is integrally formed with the upper frame and the lower frame. The metal clamping plate is provided with oil passage holes for the flow of lubricating oil filtered by the outer filter layer.

[0012] The addition of a metal clamp plate integrally molded with the upper and lower frames significantly enhances the overall structural rigidity and mechanical strength of the self-filtering assembly. The integrated design allows the metal clamp plate, upper frame, and lower frame to form a robust overall framework, better resisting vibrations and pressure fluctuations generated during bearing operation and preventing the filter layer from deforming under stress, thus affecting sealing and filtration efficiency. The oil passage holes on the metal clamp plate provide a dedicated and unobstructed flow path for the lubricating oil initially filtered by the outer filter layer, enabling it to flow efficiently to the inner filter layer for secondary filtration. This structure avoids disordered diffusion or stagnation of lubricating oil between filter layers, optimizes the oil flow path, improves lubricating oil renewal efficiency, and ensures a continuous and sufficient supply of clean lubricating oil to the bearing. Alternatively, the metal clamp plate can be designed as an annular plate structure with a central hole. The oil passage holes can be a series of fan-shaped or oblong holes arranged circumferentially around the central hole. These channels not only provide the oil passage area, but their specific edge structure also guides and distributes the oil flow.

[0013] Furthermore, the oil passage holes are distributed in pairs along the same radial extension line of the metal clamp, and multiple sets of oil passage holes are distributed at intervals along the circumference of the metal clamp.

[0014] Arranging the oil passages in pairs along the same radial line, with multiple groups spaced apart circumferentially, offers significant advantages. First, it increases the effective radial flow area of ​​the lubricating oil, allowing it to more evenly collect from the outer filter layer and pass through the metal clamp, reducing the possibility of localized oil flow blockage. Second, the circumferentially spaced groups of oil passages form a regular and reinforced network of support ribs on the metal clamp. These solid metal areas distributed between the oil passages constitute robust radial and circumferential reinforcing ribs, further enhancing the deformation resistance and structural stability of the metal clamp and the entire frame assembly. Finally, this layout allows the lubricating oil to undergo a brief buffering and pressure equalization process within the cavity between the metal clamp and the inner filter layer before passing through, ensuring smoother oil flow into the inner filter layer and contributing to improved uniformity and consistency of the filtration effect.

[0015] Furthermore, an oil storage interlayer is formed between the metal clamp and the outer filter layer, and the metal clamp is magnetic.

[0016] An oil-storage interlayer is formed between the metal clamping plate and the outer filter layer, creating a temporary oil buffer zone. The lubricating oil, initially filtered by the outer filter layer, can be temporarily stored here. This not only buffers oil pressure fluctuations but also allows for more time for tiny ferromagnetic particles (mainly iron and steel wear debris) carried in the oil and not completely intercepted by the outer filter layer to come into contact with the magnetic metal clamping plate. The magnetism of the metal clamping plate actively adsorbs these ferromagnetic impurities, achieving further purification of metallic contaminants in the lubricating oil. This design is equivalent to adding a highly efficient magnetic adsorption filtration process to mechanical filtration, specifically targeting the removal of the most harmful metallic wear particles, significantly improving the filtration effect, especially for submicron-sized ferromagnetic particles. Simultaneously, the adsorbed impurities accumulate in the oil-storage interlayer rather than directly clogging the filter layer pores, facilitating cleaning during regular maintenance and extending the service life of both the outer and inner filter layers.

[0017] Furthermore, the outer filter layer and the inner filter layer have the same axial thickness, and the ratio of the axial thickness of the metal clamping plate to the oil storage clamping layer and the outer filter layer is 2:3:1.

[0018] By configuring the axial thickness of each functional layer in a specific ratio, the overall space utilization and performance of the self-filtering seal are optimized. Setting the outer and inner filter layers to the same thickness facilitates the production and assembly of standardized, serialized filter media, and also ensures the consistency of filter layer deformation under pressure. Setting the thickness ratio of the metal clamping plate, oil storage jacket, and outer filter layer to 2:3:1 means that the metal clamping plate has sufficient thickness to ensure its structural strength and magnetic adsorption capacity; the oil storage jacket achieves the largest thickness proportion, providing ample oil buffer space and impurity settling and adsorption area, enhancing buffering and magnetic filtration effects; the outer filter layer uses a relatively smaller thickness, which typically means it uses filter media with high porosity and low flow resistance, focusing on high-speed throughput and coarse filtration functions, with its filtration accuracy guaranteed by pore size rather than thickness. This thickness ratio allocation rationally balances the needs of the three key functions—structural support, impurity adsorption and storage, and preliminary filtration flow—within a limited axial installation space.

[0019] Furthermore, the oil storage interlayer includes a first oil storage tank and a second oil storage tank, wherein the radial width of the first oil storage tank is smaller than the radial width of the second oil storage tank, and the radial width of the second oil storage tank is approximately equal to the radial width of the outer filter layer.

[0020] The oil storage jacket is further divided into a first oil storage tank and a second oil storage tank with different radial widths, achieving zoned guidance of the buffered lubricating oil and graded sedimentation of impurities. The narrower first oil storage tank, located closer to the inside, guides and accelerates some oil flow directly to the oil passage holes of the metal clamp. The wider second oil storage tank occupies the majority of the space, with a radial width comparable to the outer filter layer, meaning that lubricating oil flowing out of most of the outer filter layer first enters this spacious buffer area. In this area, the oil flow velocity decreases, which is conducive to the initial sedimentation of heavier non-magnetic solid particles in the oil under the action of gravity. At the same time, due to the large contact area with the magnetic metal clamp, the adsorption and capture efficiency of ferromagnetic impurities is high. This dual-tank structure creates an optimized process of sedimentation, adsorption, and then guidance. The lubricating oil slows down, settles, and is magnetically adsorbed in the spacious second oil storage tank. The initially purified oil is then guided by the first oil storage tank to flow more orderly to the oil passage holes for the next stage of filtration, thereby improving the efficiency of the entire impurity treatment process. Attached Figure Description

[0021] Figure 1 This is a cross-sectional structural diagram of an embodiment of the present invention; Figure 2 This is a schematic diagram of the front structure of the metal clamping plate according to an embodiment of the present invention; Figure 3 This is a partially enlarged structural diagram of the filter component in an embodiment of the present invention; Figure 4This is an equivalent stress cloud diagram of the sealing element in an embodiment of the present invention; Figure 5 This is a cloud diagram showing the magnitude of the reaction force / resultant force in an embodiment of the present invention; Figure 6 This is a diagram showing the pressure test of the seal in an embodiment of the present invention. Detailed Implementation

[0022] An embodiment of the present invention provides a self-filtering seal for bearings, such as... Figure 1-6 As shown: It includes a sealing lip 1 that provides sealing, a frame 2 that supports and shapes the sealing lip 1, and a self-filtering assembly 3 disposed inside the frame 2. It is used to replace traditional bearing sealing and grease lubrication methods, allowing the bearing's rolling track to communicate with the lubricating oil environment of the gearbox system and receive clean lubrication.

[0023] Specifically, the sealing lip 1 is made of an elastic material (such as rubber or polyurethane) and includes an upper sealing lip 11 and a lower sealing lip 12 facing outwards from the bearing to prevent external contaminants from entering. The skeleton 2 is typically made of a rigid metal material and includes an upper skeleton 21 that is fitted and supports the upper sealing lip 11 and a lower skeleton 22 that is fitted and supports the lower sealing lip 12.

[0024] The self-filtering assembly 3 is disposed between the upper frame 21 and the lower frame 22, forming the only communication channel between the bearing rolling track and the outside (i.e., the gearbox oil chamber). Its main function is to allow lubricating oil to pass through while filtering out solid impurities in the oil. The self-filtering assembly 3 includes an outer filter layer 31, a metal clamping plate 32, and an inner filter layer 33 arranged sequentially from the outside to the inside. The outer filter layer 31, closer to the outside (gearbox oil chamber), has a relatively large pore size and is used for preliminary filtration of the lubricating oil, intercepting larger particles of impurities. The inner filter layer 33, closer to the bearing rolling track, has a smaller pore size than the outer filter layer 31 and is used for fine filtration of the pre-filtered lubricating oil, ensuring that the lubricating oil entering the bearing rolling track has extremely high cleanliness. In a preferred embodiment, the pore size of the outer filter layer 31 is designed to be no greater than 1 μm, and the pore size of the inner filter layer 33 is designed to be no greater than 5 μm, to meet the basic cleanliness requirements of the oil in the gearbox. The outer filter layer 31 and the inner filter layer 33 can be fixed between the upper frame 21 and the lower frame 22 by means of bonding, vulcanization coating or mechanical pressing.

[0025] The metal clamp 32 is located between the outer filter layer 31 and the inner filter layer 33, and is preferably integrally formed with the upper frame 21 and the lower frame 22 (e.g., by stamping or casting). This greatly enhances the structural strength and integrity of the entire frame 2 and the self-filtering assembly 3. The metal clamp 32 has multiple oil passage holes 321 for the flow of lubricating oil that has been pre-filtered by the outer filter layer 31. To improve the flow efficiency of the lubricating oil, the diameter of these oil passage holes 321 is designed to be relatively large. Figure 2 As shown, the oil passage holes 321 are arranged as follows: every two oil passage holes 321 form a group and are distributed on the same radial extension line; multiple groups of such oil passage holes 321 are evenly and intermittently distributed along the circumference of the metal clamp 32, thereby maximizing the flow area within the limits allowed by the structure.

[0026] An oil storage jacket 34 is formed between the metal clamping plate 32 and the outer filter layer 31. This oil storage jacket 34 can temporarily store a portion of the lubricating oil filtered by the outer filter layer 31, serving as a buffer and stabilizing agent for the oil flow. More importantly, the metal clamping plate 32 itself is magnetic, making it a magnetic adsorption component. When lubricating oil containing fine ferromagnetic metal particles flows through the oil storage jacket 34, these metal particles are attracted by the magnetic metal clamping plate 32, thereby achieving iron removal and purification, further protecting the bearing.

[0027] To optimize structural performance and filtration efficiency, the axial thicknesses of each component layer have a specific proportional relationship. In this embodiment, the outer filter layer 31 and the inner filter layer 33 are designed to have the same axial thickness. The axial thickness ratio of the metal clamping plate 32, the oil storage jacket 34, and the outer filter layer 31 is set to 2:3:1. This ratio ensures that the metal clamping plate 32 has sufficient thickness to provide stable support and sufficient magnetic strength, while also leaving ample space for the oil storage jacket 34 to perform its oil storage and magnetic adsorption functions.

[0028] like Figure 3 As shown, the specific structure of the oil storage jacket 34 can be further optimized, including a first oil storage tank 341 and a second oil storage tank 342. The radial width of the first oil storage tank 341 is smaller, while the radial width of the second oil storage tank 342 is larger. Preferably, the radial width of the second oil storage tank 342 is approximately equal to the radial width of the outer filter layer 31. This design allows the oil storage jacket 34 to fully utilize the radial space of the self-filtering component 3, improving the oil storage capacity and the effect of impurity sedimentation and adsorption. As a preferred embodiment, the axial width ratio between the first oil storage tank 341 and the second oil storage tank 342 is 1:2.

[0029] The working principle of this self-filtering seal is as follows: Lubricating oil in the gearbox system flows from the outside to the inside of the bearing under pressure or circulation. The lubricating oil first contacts and penetrates the outer filter layer 31, where larger impurities are intercepted on the outside of the outer filter layer 31. After preliminary filtration, the lubricating oil enters the oil reservoir 34, where the flow rate decreases, and ferromagnetic metal particles are attracted by the magnetic metal plates 32. Subsequently, the lubricating oil passes through the oil passage holes 321 on the metal plates 32 and reaches the inner filter layer 33. After fine filtration by the inner filter layer 33, smaller impurities are further filtered out. Finally, the highly clean lubricating oil passes through the inner filter layer 33 and enters the bearing's rolling track, achieving bearing lubrication. Throughout the process, the upper sealing lip 11 and the lower sealing lip 12 ensure a static seal between the seal and the bearing and mounting cavity, while the self-filtering assembly 3 enables dynamic and clean exchange of lubricating oil. This design eliminates the need for separate grease injection for the bearings, allowing them to directly use the lubricating oil from the gearbox system. This saves on grease costs and maintenance procedures, completely resolves potential compatibility issues between two different lubricating media, and ensures that the bearings always operate in clean oil through multi-stage filtration and magnetic adsorption.

[0030] To verify the performance difference between this embodiment and a seal that is not hollowed out, this embodiment analyzed and tested its pressure under different environmental conditions using CAE software. Figure 4 - Figure 6 .

[0031] from Figure 4 It can be seen that the maximum contact stress calculated under the minimum interference condition of sealing lip 1 is 2.8 MPa, which is close to the optimal sealing stress range of 3~5 MPa. This ensures a tight fit with the outer ring of the bearing while avoiding excessive wear of the lip due to excessive interference.

[0032] from Figure 5 It can be seen that the maximum stress of skeleton 2 is 85 MPa, which is far lower than its yield strength (205 MPa). The deformation is only 0.03 mm, which provides reliable rigid support for the sealing substrate, making it difficult for the seal to come out. The calculated value of the current structure pull-out force is about 78 N.

[0033] from Figure 6 It can be seen that when the extrusion force of this embodiment was verified under both low temperature (-40℃) and high temperature (90℃) conditions, no detachment occurred.

[0034] It can be seen that in this embodiment, a portion of the seal is hollowed out to accommodate the self-filtering component 3, but its mechanical properties are comparable to those of a seal without hollowing out the interior.

[0035] The above embodiments are merely one preferred embodiment of the present invention. Ordinary variations and substitutions made by those skilled in the art within the scope of the technical solution of the present invention are all included within the protection scope of the present invention.

Claims

1. A self-filtering seal for bearings, comprising a sealing lip and a skeleton disposed therein, characterized in that: The sealing lip includes an upper sealing lip and a lower sealing lip. The skeleton includes an upper skeleton and a lower skeleton located in the upper sealing lip and the lower sealing lip, respectively. A self-filtering component is provided between the upper skeleton and the lower skeleton. The self-filtering component is used to connect the bearing rolling track with the outside and filter impurities in the external oil.

2. The self-filtering seal for bearings according to claim 1, characterized in that: The self-filtering assembly includes an outer filter layer disposed on the side closer to the outside and an inner filter layer disposed on the side closer to the rolling track, wherein the pore size of the outer filter layer is larger than that of the inner filter layer.

3. The self-filtering seal for bearings according to claim 2, characterized in that: The pore size of the outer filter layer is ≤10μm, and the pore size of the inner filter layer is ≤5μm.

4. The self-filtering seal for bearings according to claim 2, characterized in that: The self-filtering assembly also includes a metal clamp plate disposed between the outer filter layer and the inner filter layer. The metal clamp plate is integrally formed with the upper frame and the lower frame. The metal clamp plate is provided with oil passage holes for the flow of lubricating oil filtered by the outer filter layer.

5. The self-filtering seal for bearings according to claim 4, characterized in that: The oil passage holes are distributed in pairs along the same radial extension line of the metal clamp, and multiple sets of oil passage holes are distributed at intervals along the circumference of the metal clamp.

6. The self-filtering seal for bearings according to claim 4, characterized in that: An oil storage interlayer is formed between the metal clamp and the outer filter layer, and the metal clamp is magnetic.

7. The self-filtering seal for bearings according to claim 6, characterized in that: The outer filter layer and the inner filter layer have the same axial thickness, and the ratio of the axial thickness of the metal clamping plate to the oil storage clamping layer and the outer filter layer is 2:3:

1.

8. The self-filtering seal for bearings according to claim 6, characterized in that: The oil storage interlayer includes a first oil storage tank and a second oil storage tank. The radial width of the first oil storage tank is smaller than the radial width of the second oil storage tank, and the radial width of the second oil storage tank is approximately equal to the radial width of the outer filter layer.

Images